Past Scars are Present Nightmares
by SparklingPandaBear
Summary: When the Gray's arrive at the London Institute, they immediately befriend Jem and Will. Tessa is drawn to Will, with his haunted blue eyes that have seen to much. And Nate, to Jem with his mysterious illness that is slowly but surely killing him. Will they be able to find a cure for Jem? Or will Will's past come back to haunt them all? M for swearing. I only own the plot. AU OOC
1. Chapter 1 The First Meeting

It was a cold winters day when twelve-year-old Tessa, and fourteen-year-old Nate Grey arrived at the London Institute. But then again, almost every day was cold in London. The polite but quiet man that had delivered them to the Institute had dropped their luggage beside them, knocked on the massive front door, got back into the car and drove off without a word.

The door opened, and a small woman with thick, dark brown hair, brown eyes and a kind face appeared.

"Theresa and Nathaniel Grey, right?" she asked them. When they confirmed this, she said "Well come in, out of the cold then. You'll end up freezing to death"

They walked inside to see a corridor lit with witchlight on the walls and a chandelier in the middle. She led them into a room with a blazing fire. The lady turned to Tessa and Nate.

"Now then, that should heat you up. My name is Charlotte Branwell. Me and my husband, Henry, run the Institute. Will, Jem and Jessamine are the only other children here. Will can be quite the handful, but Jem manages to rein him in."

"And by 'handful', you really mean 'a complete and utter nuisance'" said a new, amused voice. It sounded British but with a faint trace of Chinese.

The voice belonged to a boy with dark brown hair and eyes. Both seemed to have a silvery tint. He was followed by a boy with hair as black as night and eyes the striking blue of a cloudless sky. Both were dressed in Shadowhunter gear. Both looked to be a little younger than Nate.

Blue-eyes looked towards brown-eyes with mock betrayal.

"I resent that! My ego is bruised."

"I think your ego will survive, Will"

_Ahhh_ Tessa thought _Blue-eyes is Will, so that must mean brown-eyes is-_

"I'm James Carstairs. Most people just call me Jem though."

Brown-eyes-_Jem-_ reached his hand out for Tessa to shake. She took it while telling him:

"I'm Tessa Gray, and," pointing towards Nate said, "this is my brother Nate."

He moved from Tessa to shake Nate's hand. They got into a quiet discussion about cars or whatever teenage boys chat about these days. Will walked over towards Tessa and reached out a hand. She took it.

"William Owen Herondale," he had a faint Welsh accent and his eyes seemed to sparkle with amusement and mischief. "I go by Will though"

"Where is Jessamine?" Charlotte asked suddenly

"Headache" replied Wil and Jem simultaneously, as if this was a normal occurrence, "well that's what she _said_ anyway" Will continued with an amused glance towards Jem, "personally, I think she just didn't want to go to training"

"Yes well, I'll go check on her all the same." She left the room while yelling behind her "Give the Gray's a tour of the Institute."

"Well come along then," Will said, "We haven't got all day."

* * *

Will and Jem showed Tessa and Nate the numerous bedrooms, the glorious ballroom, the humongous library-which is where Tessa would most likely be spending majority of her time-, the lounging area, the dining room, the kitchen-where Will stole sweets for the lot of them- and finally the training room.

"Me and Will were about to train before you came, want to join?"

Tessa nodded her head in excitement.

They started off just joking and laughing while doing stretches. Of course, Will quickly got bored of this and wanted to start sparring. Tessa offered to spar with him.

"You're half the size of me. I'll take you down in half a minute" Will argued.

"Don't underestimate Tessa, Will." Nate warned. "She's one of the best Shadowhunters in New York."

"Alright then, come on"

Will-rather reluctantly-led the group to the sparing ring. Will and Tessa each grabbed a training blade while Jem and Nate stood to the side. Will got into the fighting stance, and Tessa followed.

"Last chance to back out" Will said cockily.

Tessa just smiled and raised her blade. Will brought his blade down to meet hers. And the chase was on. It was an endless game of cat-and-mouse. Both as good as each other. Neither wiling to let the other win. When Will feinted Tessa was there to block him. When Tessa slashed at Will's chest, he was there to parry her. Eventually Tessa managed to duck between Will's legs and kick them out from behind him. He landed with a thud on the floor. Tessa kicked his blade away and held hers to his throat.

"Lesson one of training" Tessa said while panting slightly, "_Never,_ under _any _circumstance, underestimate your opponent."

Will just looked her with complete and utter astonishment. She removed the blade from his throat and reached down a hand to help him up. He grasped it gratefully and hauled himself to his feet.

"Holy _shit_!"

Will and Tessa turned towards Jem and Nate. Jem looked as shocked as Will was. Nate just looked proud of his younger sister.

"How did you do that?" asked Jem, still completely and utterly shocked out of his mind. "No one has _ever _beaten Will before."

Tessa just smiled, "Well now someone has."

* * *

There was a storm that night. Tessa could never sleep in stormy weather. She hadn't a clue _why,_ she just_ couldn't_. When she was younger, she'd try and try and try again, she was given sleeping potion after sleeping potion, but nothing had ever seemed to work. After a while she gave up trying.

She walked downstairs to get a drink. She opened the door of the kitchen, only to walk into another wall. A wall that grunted. The wall reached over to the light switch and flicked it. The kitchen flooded with light. Tessa looked up to see Will blinking sleepily down at her.

"What are you doing up?" Tessa asked.

"Can't sleep" he murmured.

Tessa looked up, into his eyes. They were half closed. Will himself looked like he was about to collapse from exhaustion.

"Will," Tessa said, "you're obviously exhausted. C'mon, I'll take you up to bed."

He shook his head.

"Why not? You look as if you're about to just drop to the floor and pass out."

He just sighed exasperatedly and ran his fingers through his hair. Even that action seemed tired.

"Well then, if you're not going to go to sleep, you can keep me entertained."

She reached out to grab his wrist, but the moment they made contact, he flinched and yanked his hand away.

Will mumbled an apology, saying something about how he was jumpy this during storms. Tessa knew he was only telling her half the truth but didn't press him. He obviously didn't want to talk about it, and she wasn't about to force him into talking to her. _After all_ Tessa thought_ We haven't even known each other a day. _

Tessa led Will to her room, only barely managing to find it in the maze of corridors. Will followed silently behind her. When they reached her room, Tessa beckoned him inside. She sat on one side of her bed, leaning against the headboard. She patted the space next to her, signalling to Will to sit down. He sat down next to her and mimicked her position.

"Why are you awake?" he asked her suddenly.

Tessa shrugged her shoulders and said, "I've never been able to sleep during a storm. Don't know what it is that keeps me awake but I'm never tired the day after either. Not until I_ actually,_ go to sleep. Then I pass out. What about you?" when Will opened his mouth Tessa quickly said, "And don't give me any of that, 'I can't sleep' bullshit. I saw you in the kitchen, you looked about ready to fall asleep on the kitchen floor. You still do. I can tell you're struggling to keep your eyes open."

Will looked at Tessa for a long moment. Finally, he said, in hushed voice-almost as if he was ashamed of it- "Nightmares". He looks down, embarrassed. She reached over and grabbed his hand slowly, so that he wouldn't jump. She gave it a gentle squeeze. He looked up and locked eyes with her. He smiled sleepily, but genuine. Tessa knew the only way to get him to sleep was to distract him. They chatted about nothing and everything. When Tessa asked about his parents, Will's face grew very dark.

"My parents are assholes." He said simply.

"What about siblings? Have you got any?"

"One sister," He said, "I used to have two, but she was murdered during the winter"

"I'm sorry, Will,"

"Don't be. You didn't kill her," He spoke bitterly "After all, I would know. He made me watch"

* * *

The flashbacks were coming full-force now. There was nothing Will could do to stop them. He squeezed his eyes shut. He could feel Tessa beside him, holding his hand, whispering reassuringly to him, but it was like he was watching them. Watching like a spectator from the stands of a football game. He felt like this was happening to someone else, but not him.

And then suddenly he wasn't there. He was a seven years old boy in Wales, Cadair Idris to be exact. He was on the floor of the living room. His deadbeat father was hitting him, punching him, kicking him. Hurting him wherever he could.

Distantly he could hear Tessa asking him if he was okay. So, he told her. He told her _exactly_ what was going on inside his head.

He told her about the countless hours of beatings that him and Ella had to go through to protect Cecy. How he used to be a good father, until he lost the manor in a poker match. How he'd spend hours upon hours at the local pub trying to win back their money and only succeeding in losing more of it. How his mother had to work double shifts until she got fired from work and eventually got caught up in the alcohol as well. The more his father lost, the more he got angry. The more he got angry, the more scars he'd give his children. The more scars he gave, the more he'd go to the local pub to drown out his sorrows and gamble away more of his money.

And then one day he came home. He was different. More sober than usual. Not completely wasted. Will and Ella had hoped this meant a change. Maybe, for once, he'd won something? But no. That wasn't why he was sober. It was because he'd had a task to compete. He'd somehow gotten it into his head that it was Cecily's fault he never one anymore. He had claimed that "he had always won before she was born".

All the children were sleeping and so was his wife. He had snuck out of bed and grabbed a dagger. He had crept into Cecy's room, but she was awake. She saw him lift the dagger and had screamed. Hearing the commotion, Will and Ella- their mother was still passed out from all the alcohol-had sprinted into their younger sibling's room. Their father was bringing the blade down. Will and Ella had sprinted towards him, but Ella had gotten there first and had shoved him off Cecily.

The next morning, Will had woken up, only to be knocked out again. He had woken up for the second time that day sitting on the armchair in the living room. Cecily was curled up in a ball, crying into his shoulder. He had immediately wrapped his arms around her and pulled her closer. He had looked over her shoulder to see Ella tied to the wall and their father beating her senseless and yelling profanities at her. Will had tried to get up to help her but his legs were bound by a rune. He had been stuck there, holding his little sister as tears streamed down both their faces.

Eventually their father took a knife to put Ella out of her misery. He hadn't made it quick. He had made it gruesome and horrible. Will hadn't wanted to watch so he buried his face into Cecily's hair, trying to block out the sounds of one sister's sobs and the other's screams.

Eventually the screams had stopped. Will had looked up from Cecily's hair and had immediately wished he hadn't. He had felt like running to bathroom and vomiting, the image was that gruesome. Ella was still hanging from the wall but now she was a mess. Blood had been dripping from her mouth and pouring from a gaping hole in her chest. There had been a puddle of it on the floor at her feet. The dress she'd worn was one of her favourites. What had used to be a simple blue knee-length dress was now in tatters and a horrid red colour. She had been pale and her eyes. Eyes that would haunt Will for the rest of his life Eyes that had once been a bright blue, full of life, were now pale and dead. That had been when the realisation had set in. She had died. Will's older sister had died. And it was only then that he had distantly realised, thunder had been shaking the house and lightening had been lighting the room.

* * *

Tessa had held him as he'd recounted the story of his childhood to her. He'd never been more grateful though, as she'd wiped his cheeks free of tears that he hadn't even realised he'd been shedding. She'd held him all through the storm, as sobs wracked his body until they were just quiet little things. She held him as he fell asleep in her arms. And for once, Will fell into a dreamless sleep during a storm.

* * *

Something passed between the two that night. As twelve-year-old Tessa Gray held thirteen-year-old Will Herondale in her arms, she realised she didn't _want _to be anywhere else. She _wanted_ to comfort the black-haired boy. And, as Will was held by Tessa, he realised that he wouldn't_ want_ to be in anyone else's arms.

From that day onwards, the duo was inseparable. In a storm, Will always came to Tessa's room for comfort, and Tessa was always awake. She soon found that she _could_ sleep during storms, but only if Will was with her. They both needed each other. And neither was ready to give the other up. The two were the best of friends, and always would be.

* * *

**This is my first Fanfiction so _please please please_ review. It would be greatly appreciated. Critism is welcome.**


	2. Chapter 2 Eavesdropping on the Enclave

"_Will_," spoke an annoyed, stern but familiar voice, "Apologise to Jessie for stealing her mirror."

Tessa laughed quietly to herself, as she readied herself for the day. In the two and a half years since Tessa had gotten to the Institute, she had come to know that Will wasn't someone who said 'sorry'. The thought of Will apologising was an amusing one. _Especially _Tessa thought _to Jessamine. _There'd be more chance of looking out your window and seeing pigs flying than hearing the word 'sorry' come out of William Herondale's mouth.

Tessa grabbed a towel as she walked out of her room. Sure enough, there was Will, Jessamine and Charlotte. Will and Charlotte seemed to be having a staring-or rather _glaring _\- contest that, if his smug look was anything to go by, Will was winning.

Will was leaning against the far wall of the hallway they were in. No one had noticed her yet, so Tessa took the time to examine everyone. Will was wearing his usual ensemble of a t-shirt and jeans. His black hair was wet, so she assumed he had just come out of a shower. His eyes sparkled with amusement as he stared stubbornly at Charlotte. Jessie was in a way-to-fancy, frilly dress and was glaring daggers at Will. The expression 'If looks could kill' came to mind. Charlotte was in a significantly-less-fancy-but-still-fancy dress. Suddenly, Will's gaze shifted from Charlotte to Tessa and immediately softened. And then he did something nobody expected.

"I'm sorry Jessamine"

Granted he didn't _sound _or _look_ sorry and he had his little smirk on, that just screamed: _I'm lying! Don't trust me! _But it was an apology all the same.

There was a beat of silence where everyone just stared at him in complete shock until:

"_Hmph" _

Jessamine stormed off, Charlotte trailing after her mumbling a few incoherent words as she left. Will straightened up from his slouched position on the wall and walked over to Tessa

"Enjoy the show?"

"Oh _yes_, how could I not?" Tessa answered rather sarcastically.

Will glanced at her, amused by her tone. By now they had walked the short distance from Tessa's room to the bathroom across the hall. They both stood there a moment just enjoying the others presence. A look flashed across Will's face, but it was gone before she could decipher it. Suddenly the door opened, scaring Tessa. Will, however, just laughed at her. He immediately struck up a conversation with Jem, who had been the one to open the door. After apologising to Tessa for scaring her, Jem walked on with Will, who was promising to save her some scones if she hurried her ass up.

* * *

Breakfast was uneventful. Well, as uneventful as breakfast with Will Herondale and the Lightwood siblings can be.

The reason everyone was 'dressed up' was because of the fact that the whole Enclave was coming for dinner at the Institute. Charlotte and Henry had to go to a meeting in the library, so they wouldn't get a chance to change. Jessamine didn't actually _need _to be dressed up, but it was Jessamine. She dressed however she wanted, whenever she wanted, and no one could stop her.

Will, true to his word, had saved Tessa a scone, which she was now buttering. She sat on one side of Will, with Jem on Will's other side. Jessamine sat at the head of the table. Sitting across from Tessa was Nate-who was looking increasing uncomfortable with every second that passed. Across from Will and Jem was none other than Gabriel and Gideon Lightwood-hence why Nate was looking so uncomfortable. Sophie and Bridget walked around everyone, placing fresh scones and fried bacon on the table.

Everything was going relatively well- apart from the occasional kick under the table to Gabriel from Will, or vice versa-until Will decided to say five simple, little words, that to anyone else would seem innocent, but coming from Will Herondale's mouth, it was basically a death sentence.

"I have something to say"

Everyone froze. There was a muttered "Shocker" from Gabriel. Tessa and Jem looked towards each other with alarm before looking at Will. Jem's face portrayed the worry Tessa was feeling. Whatever Will was going to say, it wasn't going to end well. He looked towards Jem with a conspiratal wink. Jem, in turn, groaned and rested his head on the table in front of him.

"Well" Tessa said, "don't keep us waiting"

Will looked to her when she spoke, and she could see the mischief in his eyes. This was going to go bad. Very, very, _very_ bad.

"Tess, you've got to realise this was an extremely traumatic time for me. So, me relaying this message to the Lightwoods is an extremely difficult task. But alas, it is only right that I tell them." Will, ever the dramatic, paused for anticipation. Until finally he spoke the words that doomed them all to Hell. Looking straight at the Lightwoods, all traces of amusement gone from his face apart from an evil glint in his eye, he said: "I saw your father shagging a demon" He then proceeded to slump down on his chair, as if he had a huge weight lifted off of his chest from that sudden revelation.

A lot of things happened then. There were collective groans of annoyance from Jem, Nate and Tessa. There was a clatter as Sophie dropped a teapot in shock, and Bridget went to help her clean it up. And finally, there was the screeching of chairs as Gideon and Gabriel to stood up to give Will a piece of their minds. And Will just sat there, slumped in his chair, with a smirk on his face, watching the disastrous scene before him unfold.

The Lightwoods looked murderous but seemed unable to form words. Gabriel was the first to recover.

"_How dare you?! _You have _no _right to say those preposterous _LIES!"_ But that was the thing about Will. He didn't lie. So, no matter how rude the words had been, Tessa didn't doubt for a second that they weren't true. But Gabriel was still shouting and glaring at Will with all his might. And Will just kept on smirking up at him.

They kept on this tirade until, Charlotte came in telling them to "shut the hell up."

* * *

Tessa, Nate, Jem and Will hid behind one of the bookcases in the library, where the Enclave meeting was being held. They had snuck in when the adults had taken a break.

Suddenly the library door swung open and in came the Enclave.

"So, what are we supposed to do?" asks Charlotte, "We can't just go around killing mundanes at random."

"No one is saying that." A man replied. "We just need to find a way to catch them in the act."

"Well, do tell, how you suppose we do this, George" asks Benedict Lightwood.

"Well you said that the murders always happen within a five-mile-radius of the last one, and that they always happen in an alley, correct?" Benedict must've nodded his head because the man-George continued, "Well then why don't we set up patrols at the alleys that are within a five-mile-radius. We're bound to catch them that way." There was a silence as the Enclave considered this.

That's when Will, the idiot, decides to take a peek.

"WHO DARES EAVESDROP ON AN ENCLAVE MEETING?!" roared Benedict Lightwood.

Busted.

Everyone looks towards Will. He just shrugged and walked out with his trademark smirk in place. Tessa, Nate and Jem soon follow suit, but to the four's surprise, they aren't the only underaged Shadowhunter's there. Gabriel and Gideon are standing two bookshelves over with guilty looks on their faces. Benedict's face was turning an unflattering shade of purple-kind of like what Gabriel's face had looked like when Will had told him of his father's nightly affairs.

Charlotte just looked unsurprised and slightly annoyed-although Tess suspected it was more for them getting caught rather than the actual _eavesdropping _part.

"Will Herondale" Benedict spat, "Why am I not surprised to find you here?"

"Well I don't know, Benedict?" Will had a look on his face that suggest he knew exactly why Benedict wasn't surprised. "Why don't you enlighten us all with your fascinating motives for not being surprised. It isn't like you're in the middle of a meeting or anything."

If it's possible, Benedict's face turned an even darker shade of purple.

Benedict opened his mouth-probably to yell something horrible to Will-but suddenly he turned his gaze to the other two Lightwoods in the room.

"Gideon and Gabriel" he said, his voice that scary-calm that adults use when they're extremely angry. "What in utter God's name, are you two doing in here?"

"Yes, do tell, Gabriel. I've been wondering the same thing myself."

Benedict-choosing to ignore Will's interruption-carried on with his rant.

"-this is something I'd expect a _Herondale_ to do but not a _Lightwood_. My own _flesh and blood_. I thought you two boys were better than that."

_Jeez, _Tessa thought looking towards her own group of troublemakers, who had, thankfully, been forgotten about for the time being, _I thought Will was dramatic. He's got nothing on Benedict Lightwood. _You'd think it had been Gabriel and Gideon caught canoodling with demons rather than simply eavesdropping on and Nate seemed to be thinking the same thing. Will just looked amused. As per usual.

After what seemed like an eternity, Benedict stopped blabbering on about 'shame on the Lightwood name'-insert snort from Will here- and 'severe punishments when they all go home'. Everyone then turned their gazes to Nate, Jem, Will and Tessa. It was so quiet you could hear a pin drop. It was Charlotte who broke the silence.

"What on Earth are you four doing here?" Of course, the group turned to Will, who just shrugged and said:

"Exactly what Benedict said we were doing. Eavesdropping on Enclave meetings."

* * *

Will and Gabriel stood at opposite ends of the hall, glaring at each other. Jem and Nate stood on one side of Will and Tessa on the other. Gideon stood beside Gabriel, likely for the same reason as the others stood beside Will-to stop him if a fight were to break out.

"I told you it was a bad Idea" said Tessa.

"It wasn't a bad idea, Tess, you just didn't want to do it because you're a goodie-two-shoes." Will muttered quietly.

"I most certainly am _not_!" claimed Tessa, who had clearly heard him.

"Oh, yes you are Tessa. Who is it that always says, 'This is a bad idea', before we sneak into one of these meetings? It certainly isn't Jem or Nate."

"Just because I'm the _sensible _one- "

"You're not _sensible_, you're a _goodie-two-shoes_!"

"Oh hush," and with that last comment, Tessa hit Will on the back of the head.

Meanwhile, Jem, Nate, Gideon and Gabriel had been watching the exchange with amused looks on their faces. It was silent for a few moments until-

"She had a fair point though, Will. She _is _the sensible one of the group,"

"Ouch." Said Gabriel, "Betrayal by your own soon-to-be-_parabatai_. Can't say I blame him, though."

Will, who was clearly in a bad mood, gave Gabriel the dirtiest look that would've sent the Devil himself crying for his mother. It was quiet for a few moments until Will announced that he was going to get a sandwich. He turned to Tessa, Nate and Jem and asked if they were coming. They each shrugged their shoulders and began to follow him out, until Gabriel Lightwood decided to say something about it.

"You know we're not allowed to leave this hallway, until the Enclave finish their meeting."

Will turned to Gabriel. "I know, but I don't particularly care. But _please_, by all means, stay and wait for dear-old-daddykins to hand out punishments. I, on the other hand, am going to get something to eat because I am _starving_ and don't give two fucks what Benedict Lightwood has to say about it." With that, Will turned on his heel, and walked swiftly away, with the other three chuckling behind him.

Not swiftly enough that he didn't hear Gabriel muttering behind him:

"At least our father doesn't beat us for punishment."

Will froze in the middle of the hallway. Tessa glanced towards Nate and Jem to see anxious expressions on their faces that she was sure was mirrored on her own. Slowly, Tessa approached Will's still form. She laid a hand on his shoulder. His face was blank, devoid of emotion.

"He's not worth it, Will," Tessa murmured, just loud enough for him to hear, "Let it go"

His face turned hard and cold, "The _Hell_ I will!"

"_Will_!" Tessa shouted, but it was already too late. Will had already stormed over to Gabriel Lightwood and, before anyone could move to stop him, punched him in the face. Gabriel's head whipped to the side and his hand went up to cover his now-bleeding nose. Nate and Jem ran over, and each grabbed one of his arms. They pulled him back as Tessa ran over. Tessa put her hands on Will's chest.

"You _bastard_!" yelled Gabriel furiously, but it was muffled from his hand, that was now also covered in blood.

Tessa turned her head to look at him disbelievingly. "You're hardly one to talk," she exclaimed incredulously, before turning back to Will.

He was still fighting off Jem and Nate and didn't seem to even notice Tessa was there.

"Will, look at me." No response. "_Will_!" Still no response. Tessa grabbed his face and forced him to look down towards her.

"Will," she breathed, "Stop." And he did. He finally locked eyes with her. He slumped down in Nate and Jem's arms and rested his forehead against hers. She could see the anger fading quickly from his eyes, only to be replaced by sadness. She rubbed her thumb against his cheek, calming him as he closed his eyes in contentment.

However, their peace was short lived.

The door to the library slammed open and Benedict Lightwood's significantly-less-purple-but-still-purple face appeared behind it, followed by Charlotte and the rest of the Enclave.

"What, in the Angel's name, is the meaning of all this noise?" Benedict shouted.

Tessa hadn't moved her gaze from Will, but now she did. She sent a glare to Benedict before saying, "Why not ask your son? After all, he started it."

* * *

**Sorry for the really long wait! Review please!**


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